Adolescents in mental health treatment are at greater risk for HIV and other STIs than their peers due to an earlier age of onset of sex, less protected sex, more sexual partners, and more frequent substance use. This greater risk is due to multiple factors including cognitive misperceptions, affect dysregulation, and less self efficacy. The numerous adolescents who receive mental health treatment do so in a variety of settings such as day hospital programs, therapeutic schools and residential centers. These programs offer a variety of health services but there is no efficacious HIV prevention program specifically tailored for the issues of youth in mental health treatment, other than the one described in this project. STAR (Safe Thinking and Affect Regulation) is an award winning and efficacious fourteen session group intervention that successfully targets affect regulation and cognitive monitoring in sexual situations as the key, novel elements to improve sexual safety. This fourteen session group intervention won the Rieger Award for Scientific Achievement from the American Academy of Child and Adolescent Psychiatry in 2012. It is the first and only intervention to have demonstrated an improvement in safer sexual behavior for youth in mental health treatment, a group that is at- risk and not otherwise targeted with interventions tailored for their issues. The goal of this SBIR Fast-Track project is to transform STAR into an engaging digital, multimedia format, Digital STAR (D*STAR), for easy and reliable use by care agencies that serve adolescents in mental health treatment. To transform this intervention, Virtually Better, a company with a successful history of production and distribution of cutting-edge technological interventions, has teamed with the research developers of STAR at Rhode Island Hospital and Brown University. During the two phases of this Fast-Track project, digital session development will be accomplished by an iterative process of feedback and refinement between Virtually Better, the developers of STAR, adolescents in mental health treatment, and a Community Advisory Board. The created multimedia intervention, D*STAR, will convey relevant information, offer realistic skills practice, and be engaging and enjoyable. A randomized control trial of D*STAR compared to a time-matched digital general health promotion condition will be conducted among 120 adolescents ages 13 to 18 in mental health treatment to ensure that D*STAR is efficacious in improving HIV knowledge and relevant attitudes, and increasing safer sexual behavior. This project is innovative because D*STAR will contain the essential elements of a proven, award winning intervention; its digital format will allow for reliable and consistent deliverability; it will be utilized without the need for extensively trained or highly specialized facilitators; and it will use engaging, immersive technologies that are maximally appealing to youth. Developing this high- quality implementation package for easy dissemination is essential to achieving a greater public health impact from this proven HIV prevention intervention for youth in mental health treatment.